Storage of volatile hydrocarbons



Patented May 21, 1935 A UNITED STATES STORAGE 0F VOLATILE HYDROCABBONS,

PARTICULARLY BUTANES Walter G. Whitman, Whiting, Ind., assignor to Standard Oil Company, Chicago, 111., a corporation oflndiana Application November 23, 1931, Serial No. 576,712

9 Claims.

age.

In the art of refining mineral oil for the production of motor fuels of the gasoline type, it may be desirable to blend certain low-boiling volatile liquid hydrocarbons, such as butane, with such gasoline products. These low-boiling volatile hydrocarbons may be obtained from various sources, however, it is the general practice to recover them from certain gases produced in various refinery operations, such as cracking and distillation oper ations. Also, these low-boiling volatile hydrocarbons are often removed from casing head or natural gases. Owing to the volatility of these light hydrocarbons, i. e., butanes, etc., it is often the practice to add relatively small quantities of such hydrocarbons to a gasoline to be used in the warm summer season and to add relatively larger quantities to a gasoline to be used in the cooler seasons. By means of the present invention, these volatile hydrocarbons can be regovered from available gases the year round, the excess quantities not used in the warm seasons, being stored up for the cool seasons.

The invention will be fully understood from the following detail description, taken in conjunction with the accompanying drawing which is a diagrammatic elevational view of apparatus for carrying out the present invention.

Referring more in detail to the drawing, the numeral 5 indicates a closed storage tank adapted to contain highly volatile hydrocarbons, for example, butanes, etc; The walls oithe tank 5 are preferably insulated or lagged by suitable material. The tank 5 is preferably not entirely filled with the stored liquid hydrocarbons in order to provide space for accumulation of vapors formed during storage of the volatile hydrocarbons. The vapors formed during storage are passed from the upper portion of the tank 5 through a line i to the inlet of a compressor 1 which may be operated by a suitable source of power, for example, an

and returned to the liquid hydrocarbons in storelectric motor 8. The compressed vapors are forced from the compressor 1 through a line 9, cooling or condensing coil Ill, and a line H and into a liquid-vapor separating drum i2, wherein liquefied or condensed portions separate from the 5 vaporous or uncondensed portions. The separated liquid and vapors within the drum 12 are maintained under a substantially high pressure, the liquid being withdrawn from the lower end of the drum l2 through a line 13 from which it may be 10 passed to either of a pair of branch lines l4 and 53. The branch line H is provided with a pressure reducing valve l6 and discharges into an expansion drum l1 maintained under a substantially reduced pressure, for example, approximately at- 15 mospheric pressure. The hydrocarbon liquid portion so introduced into the low-pressure expansion drum l1 undergoes partial flashing into vapors, thus cooling or refrigerating the remaining unvaporized portions of thelight hydrocarbons to substantially the same temperature as prevails in the storage reservoir 5 which may beapproximately 0 C. more orless. The cooled or refrigerated liquid portion is passed from the bottom of the drum I! through a valved line 18 and 25 into the lower portion of the storage tank 5, and the expanded cool'vaporized portions are passed from the upper end of the chamber I! through a valved line It and into the line 6, whereby the cool vapors become admixed with the vapors passing through the line 6 from the storage tank 5 to the compressor 1. If necessary for any reason, all or a portion of the liquid withdrawn from the high pressure drum or separator l2 through line i3, may be passed through valve l5 and branch line 35 20 directly into the lower portion of the storage tank 5,, the line 20 being provided with an expansion valve 2|, whereby the compressed liquid is caused to undergo expansion and be thereby re- 40 frigerated as it flows to the tank 5. However -I prefer not to operate the system in this manner as I find that the vapors released from the liquid butane at pressure reducing valve 2| set up'a violent agitation in storage tank 5 and cause greater evaporation than when the butane is admitted as a precooled liquid. In fact, the more nearly quiescent the contents of the storage reservoir can be maintained, the less the refrigeration required.

The operation of the compressor 1 is preferably controlled by means of a device responsive to the pressure conditions on the vapors in the storage tank 5. In the present embodiment one of the lead wires to the electric motor 8 is provided with a fluid-pressure operated switch connect- 2. The method of storing volatile normally gaseous hydrocarbons at substantially atmospheric pressure, which comprises maintaining in liquid form by refrigeration a body of such hydrocarbons, withdrawing portions of said hydrocarbons comprises maintaining a refrigerated body of =uch liquid hydrocarbons, withdrawing portions J1. saidhydrocarbon body which become volatilized during storage and compressing them, cooling and thereby condensing a portion of said compressed hydrocarbons, separating the resulting condensate from the uncondensed vapors and thereafter substantially reducing the pressure upon said condensate thereby flashing a portion of said condensate and effecting refrigeration thereof, separating the liquid and flashed vaporized portions, returning the vaporized portions to said compressing operation, and passing the cooled liquid portion to said stored liquid body of hydrocarbons.

4. The method of storing volatile normally gaseous hydrocarbons which comprises maintaining a refrigerated body of the hydrocarbon liquid in a closed storage chamber, withdrawing vaporized portions of said hydrocarbons and passing them to an absorption operation wherein desired hydrocarbon constituents are absorbed in a fluid absorbing medium and thereby separated from undesired excessively volatile constituents'of said vapors, heating the enriched absorbing liquid to vaporize the desired hydrocarbons and separate them from said absorbing l uid, condensing the desired hydrocarbon vapo under pressure, releasing the pressure e condensed hydrocarbon vapors and conducting only the remainingliquid condensate to said storage chamber.

5. The method of storing a body of volatile normally gaseous hydrocarbons which comprises maintaining in, liquid form a refrigerated body of such volatile hydrocarbons, withdrawing vapors evolved from said stored body oi liquid hydrocarbons, compressing and cooling said withdrawn vapors to effect condensation of desired hydrocarbonfconstituents thereof, separating the resulting condensate from uncondensed vapors passing the said separated vapors to an absorption operation wherein desired volatile hydrocarbon constituents thereof are recovered in liquid form, and passing the recovered liquid hydrocarbons together with the condensate produced in the compression and cooling step to the stored body of liquid hydrocarbons.

6. In apparatus for storing volatile normally gaseous hydrocarbons, the combination of an enlarged closed storage chamber, a compressor and condenser, conduit means for conveying vapors from said storage chamber to said compressor and condenser, a pressure separator drum provided with, vapor discharge means connected to said condenser, a flash drum connected to said storage chamber, conduit means for passing liquid from said separator drum to said flash drum, conduit means for conducting liquid'thence to said storage chamber and conduit means for conducting flashed vapors away from saidflash drum.

7, In apparatus for storing volatile hydrocarbon oils, the combination of an enlarged closed storage chamber, a compressor and condenser, means for conveying vapors from said storage chamber to said compressor, a liquid-vapor separator drum connected to the outlet of said condenser, and means for passing liquid from said separator drum to said storage chamber, an absorber for volatile hydrocarbons, means for passing vapors frdm said separator drum to said absorber, means for recovering volatile liquid hydrocarbons from said absorber, means for withdrawing vapors from said volatile liquid by reducing the pressure thereon and means for passing the recovered liquid to said storage chamber.

8. In apparatus for storing volatile liquefied normally gaseous hydrocarbons, the combination of an enlarged closed storage chamber, a compressor and condenser, means for conveying vapors from said storage chamber to said compressor and condenser, a liquid-vapor separator drum connected to the outlet of said condenser, means for passing liquid from said separator drum to said storage chamber, an absorption system, means for passing vapors from said storage cham ber directly to said absorption system, means for passing vapors from said separator drum to said absorption system, means for withdrawing recovered liquid hydrocarbons from said absorption system, means for removing the most volatile constituents from said liquid hydrocarbons and means for conducting the remaining recovered liquid hydrocarbons to said storage chamber.

9. The method of storing a body of normally gaseous hydrocarbons which comprises maintaining in liquid form a refrigerated reservoir of such volatile hydrocarbons, continuously maintaining a slight subatmospheric pressure on said body whereby loss of vapors of said hydrocarbons is entirely prevented although contamination by air is encountered due to leakage into said reservoir, withdrawing vapors of said liquid ydrocarbon body which become volatilized during storage and compressing them, condensing the compressed hydrocarbons, separating uncondensed contaminating air, expanding the liquid hydrocarbons whereby they are cooled to a temperature substantially equal to the temperature of the storage reservoir, separating flashed vapors from the cooled liquid hydrocarbons and thereafter returning the said liquid hydrocarbons only to said reservoir.

- WALTER G. WHITMAN.

May 21, 1935. A. e. WOODMAN HONEY EXTRAGTOR CONSTRUCTION Filed April 3, 1955 3 Sheets-Sheet 1 

